Patterson-Stevenson-Fontaine syndromeis a very rare syndrome characterized by abnormal development of the bones and tissues of the face (mandibulofacial dysostosis) and limb abnormalities. Physical features of this condition may include a recessed jaw (retrognathism), cleft palate, and anomalies of the external ears. Limb abnormalities may include the absence of toes, clefts in the feet, and fusion of toes together (syndactyly). These limb abnormalities together are known as split-foot deformity or ectrodactyly.

Patterson-Stevenson-Fontaine syndrome is inherited in an autosomal dominant manner. Diagnosis of the condition may be based on seeing symptoms in an individual that are consistent with the syndrome. Treatment is focused on improving the symptoms of each person.

Scientists don’t yet understand the complete picture of what causes Patterson-Stevenson-Fontaine syndrome. It is possible that a specific genetic change (mutation) that causes Patterson-Stevenson-Fontaine syndrome, but that gene has not yet been identified. Because the symptoms of the syndrome are present from birth, it is likely that the syndrome is caused by a mutation in a gene that controls the development of the face and feet.

Some people with Patterson-Stevenson-Fontaine syndrome may have all of these features, while others may only have features affecting the face or feet.

When a person with Patterson-Stevenson-Fontaine syndrome has children, each child has a 50% (1 in 2) chance to inherit the same gene change that causes the syndrome. However, Patterson-Stevenson-Fontaine syndrome reportedly shows reduced penetrance. This means that not every person with a disease-causing mutation will have features of the syndrome. Therefore, it is possible for this condition to appear to “skip” generations. If a person with the syndrome has a child with the gene change but no features of the syndrome, when this person goes on to have children, he or she may have features of the syndrome.

Patterson-Stevenson-Fontaine syndrome also shows variable expressivity. This means that not all affected people will have the same signs and symptoms, and some people may be more severely affected than others.

In some cases, a mutation that causes an autosomal dominant syndrome is inherited from a parent with the mutation. In other cases, autosomal dominant syndromes are due to new mutations that occur for the first time (de novo) in an affected person.

A diagnosis of Patterson-Stevenson-Fontaine syndrome is typically made based on a person having symptoms consistent with the syndrome. It may be possible to make a diagnosis of the syndrome before a child is born (prenatally) based on ultrasound. However, the syndrome is so rare that it would likely not be identified unless it was suspected based on family history.

Treatment of Patterson-Stevenson-Fontaine syndrome focuses on the specific symptoms present in each person. Surgeries may be available to treat some of the features of the syndrome, such as cleft palate or syndactyly. However, surgery is not available for all features of the syndrome. For people who have hearing loss, hearing aids may be available.

It is unclear whether or not intellectual disability is associated with Patterson-Stevenson-Fontaine syndrome. In one family, individuals with the syndrome had intellectual disability, but this may not have been caused by having the syndrome. In other families, intellect among people with this syndrome has been normal.

Because people with this syndrome have facial differences, it may be important to join support groups or meet people who have similar facial differences. Information about finding support groups or other affected people is listed below.